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D5.5 Three Documented 3D/VR Case Studies
CASE STUDY 3: Maltese Prehistoric Sites and Collections
Joanne Mallia, Heritage Malta
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 2
CASE STUDY 3: MALTESE PREHISTORIC SITES AND COLLECTIONS 3
ABSTRACT 3
1. Introduction – Malta’s prehistoric cultural heritage 4
2. Heritage Malta’s data 5
3. Preparation of the models for CARARE and Europeana 5
4. Publishing the models as 3D PDF 7
5. Digital Library Mapping 8
6. Conclusion 8
Acknowledgements 8
References 8
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 3
CASE STUDY 3: Maltese Prehistoric Sites and Collections
Joanne Mallia, Heritage Malta
Abstract
Created in 2002, Heritage Malta is the national agency for museums, conservation practice and
cultural heritage. As reflected in its mission statement, the responsibility of Heritage Malta is to
ensure that all the aspects of cultural heritage entrusted to it are protected and made accessible to the
general public. This translates to a multitude of functions in real life which include research,
management, conservation, interpretation, marketing, education and dissemination.
The rapid advance of technology over the last few decades has completely changed the way we
interact with information and gain knowledge. From searching online to social networking,
technology and the Internet have become an important element in many aspects of our lives, not the
least of which are research and education. This has prompted Heritage Malta to invest in the
digitisation of the historical sites and items under its care, both to create high quality records of their
current state for posterity as well as creating a tool for research, management and public
dissemination.
In order to make these resources more accessible, Heritage Malta joined the Best Practice Network
CARARE in 2009 which is a dedicated group of universities and heritage institutions that are
working towards adding records on the archaeological and architectural heritage of Europe to the
online digital library, Europeana. To the visitor, Europeana has given access to a repository of over
20 million object records, ranging from images to ancient texts, audio and video files, from 34
countries. To the heritage institution, Europeana has become a gateway to reaching millions of
visitors across the world. Already in the first nine months of 2012, the site has registered over 3.5
million visits (Europeana 2012), making it an ideal dissemination tool.
Heritage Malta has been using 3D scanning since 2005 to record its megalithic temples, which are
World Heritage sites, and will make these available as 3D PDFs through the technology options
offered by the CARARE Project. In addition, 7,000 digital records of various archaeological objects
are also being made available to Europeana through CARARE.
Keywords: Neolithic, Bronze age, megalithic temples, World Heritage Sites, 3D models.
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 4
1. Introduction – Malta’s prehistoric cultural heritage
In spite of its small size, the Maltese archipelago has a rich and varied history. Archaeologically, it is
probably best known for the imposing remains of megalithic structures dating back to the Neolithic
period of Maltese prehistory. These structures are dated to between c. 3600 BC and 2500 BC, a
period which became commonly known as the Temple Period. Some of these structures were reused
in the subsequent Bronze Age period (2400 to 700 BC). These free-standing structures, with their
characteristic D-shaped rooms flanking an open central space, were constructed from massive
limestone blocks. In most structures, well-dressed blocks form a concave monumental facade
overlooking a level forecourt whilst a large external wall delimits the structures. Considering that
they were built in a period when technology was limited to wood, stone and bone tools and society
was based on agriculture and animal rearing, it is no wonder that six of these structures have been
inscribed in the UNESCO World Heritage List since 1992 as the most characteristic examples of a
major cultural, artistic and technological development. These sites are the Megalithic Temples of
Malta, namely Hagar Qim, Mnajdra, Tarxien, Ggantija, Ta' Hagrat and Skorba Temples. (Figure 1).
Also from the same period, with its own inscription in the UNESCO World Heritage List since 1980,
is another unique site, the Hal Saflieni Hypogeum. Carved into the soft limestone bedrock of the
modern-day town of Paola, this underground site consists of three distinct layers of chambers which
were used for burial during the Maltese Neolithic period. Carved features, which mimic elements
from the contemporaneous above ground Temple sites, and red ochre paintings on the rock walls
which have survived over 4000 years, give evidence to the artistic heritage of the people who built
and used the Hypogeum. (Figure 2) .
The excavation of these and similar sites have also produced a rich and varied collection of
prehistoric artefacts which range from finely carved statuettes depicting obese human figures to
decorated pottery, stone jewellery and metal implements from the Bronze Age.
Figure 1: The Hagar Qim Temples
(Photo: Heritage Malta)
Figure 2: The chamber within the Hal Saflieni
Hypogeum known as the Holy of Holies
(Photo: Heritage Malta)
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 5
2. Heritage Malta’s data
Over the past decade, these sites have played a major role in Heritage Malta's digitisation efforts.
The archaeological collection, consisting of thousands of artefacts, is in the process of being
catalogued and photographed. Of these, approximately 6,000 records of artefacts span Maltese pre-
history from its earliest days in the Neolithic period up to Punic, Roman and Medieval times.
The approach adopted towards the architectural remains, the Megalithic Temples, had to account for
the complexity of the structure and its surfaces, some of which are decorated. It is for this reason
that, back in 2005, the first tests were made on the use of laser scanners for accurate three
dimensional recording at the Ggantija Temples in Gozo. Between 2006 and 2011, with the help of
European funds, Heritage Malta has created a 3D record for all the World Heritage Sites under its
care. Whenever possible, similar technology is now also being utilised for the documentation of
artefacts.
These models are currently being prepared for inclusion in Europeana through the CARARE project
as part of its efforts to include three-dimensional records into the digital library. However, the
combination of very complex structures, uneven surfaces and the use of high resolution laser
scanners has created models with some very particular issues. The biggest challenge is the sheer size
of the models with the high density of points recorded and the high resolution texture. This makes it
difficult to view, navigate and certainly far too large to upload onto the internet. The older models,
carried out between 2005-2008 when the technology and its application in such sites was still
developing, also present an additional challenge in the form of gaps in the model caused by lack of
data.
3. Preparation of the models for CARARE and Europeana
Work to date on preparation of the 3D models for CARARE and Europeana has focused mainly on
addressing two challenges: improving the model aesthetically and reducing its size for online
publication. Several meetings with Work Package leader, Daniel Pletinckx, have helped identify a
possible solution to the first issue which consists of utilising alternative methods of recording in 3D,
such as the image-based modelling for cultural heritage developed by the EU-funded EPOCH
project, to create point clouds for the areas where data is missing and then merging the two. The
point cloud was created using aerial images taken from the maintenance walkway which forms part
of the protective shelter over Hagar Qim during a visit by Dr. Pletinckx. With help and guidance of
specialists from the University of Malta, namely Mr. Sandro Spina and Dr. Suzanne Psaila, this
merge was tested with promising results for one of the apses/rooms of the Hagar Qim Temples.
Although the image-based point cloud is of lower quality when compared to the high resolution,
highly accurate laser scan clouds, in most areas the merge of the two point clouds fit well enough to
make an acceptable model for public presentation (Figures 3 and 4). Once testing is complete, this
process will be applied to the Hagar Qim and Mnajdra Temples models.
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 6
Figure 3: High resolution three dimensional model of the Hagar Qim Temples.
Image showing part of the external wall.
Figure 4: Merging of laser-scan based and image-based point clouds. Initial test carried out by
Dr. Suzanne Psaila. (Images: Dr. S. Psaila)
The second challenge, reducing the file size of these models to enable online publication, is also
being addressed. Again, on Dr Pletinckx's and Mr Spina's suggestion, a simplification of the mesh
has been tested on the latest of the models to be produced, the Tarxien Temples model. This has
already been successfully reduced from 760Mb to a mere 69Mb. A loss in resolution is unavoidable
but acceptable for its intended end use. However, although the reduction in size is remarkable,
further experiments will be carried out to try to reduce it further as the model is still too large for
online use.
A back-up solution, which consists of breaking up the model into smaller pieces such as a set of
rooms instead of a whole site, was also identified in case any of the preferred solutions failed for one
or more of the models.
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 7
4. Publishing the models as 3D PDF
The chosen vehicle for the online publication of these models for Europeana is 3D PDF, primarily
because it is accessible to all through a free viewer, it is easy to use and offers a number of
convenient functions such as having named views, linking certain viewpoints to the descriptive text
and allowing full 3D navigation.
Until the tests are completed on the reduction in size, efforts have concentrated on creating 3D PDF
models which contain at least one part of a site model. The 3D models within the document would
therefore be illustrating highlights of the site rather than allowing the user to see the site as a whole.
One example, “HM 3D-PDF-Tarxien temples Earliest remains.pdf” (5.83MB), is the model of the
earliest of the four Megalithic Temples which make up the Tarxien Temples complex. The
document contains a brief introduction to the site, a description of the remains, a plan of the site
which indicates the location of the area being described and the 3D model itself. The preparation of
the 3D PDF document required: segmentation of the model; simplification of the mesh reducing its
size to 25% of the original; conversion into U3D format; and finally, the assembly of the document
using Adobe Acrobat 9 Pro Extended.
Figure 5: The Venus of Malta
A second example, “HM 3D-PDF-Venus of Malta.pdf” (1.65 MB),
shows one of the iconic stone figurines originally discovered at Hagar
Qim and which now forms part of the national collection and is on
display at the National Museum of Archaeology. The layout of the
document is similar except for the site plan which has been replaced
by an image of the original.
One particular site however presents a different challenge with
regards to its online publication. This is the model of the Hal Saflieni
Hypogeum. Apart from the size of the model, the very fact that the
site is underground requires a different form of interaction from the
user - particularly when it comes to navigation. The tool used to
publish such a model needs to be able to stop the user from navigating
through the rock walls as this would only make the experience
confusing and unrealistic. Upon Dr Pletinckx's suggestion, several
solutions for this are being considered including the use of a simple
virtual reality environment where such constraints can be enforced.
However, a final decision has not yet been made.
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 8
5. Digital Library Mapping
Heritage Malta has over 7,000 records with images of archaeological objects within its digital asset
management system. All the images and metadata of these sites and artefacts, ranging from
megalithic structures (such as the "Mnajdra Temples"), to figurines (such as the "Sleeping Lady" and
"The Venus of Malta", [Figure 5]) and tools (such as "Bone Borers"), will be ingested in the
CARARE MORE repository. Figure 6 shows some of the images related to the records that will be
ingested.
Figure 6. Bone Borer, Sleeping Lady
6. Conclusion
The final step of the process is the publication through Europeana which will bring many benefits. It
will increase the awareness of the rich and varied archaeological and architectural heritage of Europe
and in particular, Malta. It will enable and encourage users to explore this heritage and to learn in a
controlled environment with information produced by specialists in the field. And, addition of 3D
capabilities to Europeana and the inclusion of three dimensional models will give users a very
different perception, or mental image, of what a site - especially ones as complex as the Megalithic
Temples of Malta - is like, giving them a completely new experience. After all, in 2012, technology
and new media have been an important part of everyday life for most people.
Acknowledgements
This work was carried out by the staff of Heritage Malta with technical assistance and support from
Daniel Pletinckx, Visual Dimension and specialists Mr. Sandro Spina and Dr. Suzanne Psaila from
the University of Malta. It was designed, delivered and funded within the EU project CARARE
(Connecting Archaeology and Architecture in Europeana, ICT Policy Support Programme).
References
Europeana (n.d.): "Europeana Professional: Facts & Figures"
http://pro.europeana.eu/web/guest/about/facts-figures
Heritage Malta (2008), www.heritagemalta.org
D5.5 Case Study of the Maltese Prehistoric
Sites and Collections 9
Mallia, J. (2008): "Bridging the gap: the Megalithic Temples in the 21st century", in Zammit, M.,
and Mallia, J., Ta' Hagrat and Skorba Ancient Monuments in a Modern World", Malta: Heritage
Malta
Pletinckx, D. (2011): “Europeana and 3D”. Proceedings Congress of the International Society for
Photogrammetry and Remote Sensing. Technical Session 9 - Interactive online 3D models. Volume
D5.5 3D Case Study of the Iberians 13 XXXVIII-5/W16. 2nd-4th March 2011 Trento, Italy.
http://www.isprs.org/proceedings/XXXVIII/5-W16/pdf/pletinckx.pdf
UNESCO (1992-2012), Megalithic Temples of Malta, http://whc.unesco.org/en/list/132
UNESCO (1992-2012), Hal Saflieni Hypogeum, http://whc.unesco.org/en/list/130